Composite nanofiber separators of polyvinylidene fluoride(PVDF) and titanium dioxide (TiO2) were prepared by electrospinning of PVDF solution containing in situ generated TiO2.The effects of TiO2 contents on the seperators structure and properties were investigated.The morphology of seperators was characterized by scanning electron microscopy (SEM)

and the fiber diameter distribution was also calculated using scnimage software.Differential scanning calorimetry (DSC) measurements were carried out to investigate seperators thermal properties such as melting point

melting enthalpy and crystallinity.The mechanical strength was determined by tensile tests.The ionic conductivity was determined by AC impedence method

and the decomposition potential was determined by linear sweeping voltammetry (LSV).The results indicate that the seperators tensile strength and elongation at break were improved remarkably after the addition of TiO2

with the maximum increase rate of 228.6% and 244.8%

respectively.The presence of TiO2 reduced the crystallinity of the seperators

which is benificial to the transfer of lithium ions.The polymer electrolytes electrochemical performance was also enhanced

and the ionic conductivity at room temperature increased from 3.9 mS/cm to 5.1 mS/cm.